1. Field of the Invention
The present invention relates to an optical fiber connector having a plug unit and a counter plug unit, as well to a method of producing same.
2. Background of the Invention
In fiber-optical transmission technology optical fiber cables are used in the form of glass fiber cables for transmitting information. In this manner low-interference glass fibers permit the implementation of transmission channels having very large bandwidths and very high transmission capacities of more than 100 megabit/sec over rather long distances. Electro-optical or opto-electronic converters on both ends of the fiber-optical light guide convert analog signals or digital signals into light variations or pulses, and vice versa. The application of optical glass fiber cables requires, however, also joining techniques which permit a loss-free transmission of optical information to the respective electronic terminals. Moreover, the demand for high transmission capacities leads to glass fiber cables which are laid in parallel and linked with the respective terminals for further connection via specifically designed connector modules which are frequently provided in the form of plug units. Such optical parallel plugs can be assumed to replace the conventional electrical parallel pin-and-socket connectors in almost all applications in the future.
By contrast to conventional electrical parallel pin-and-socket connectors, which serve to establish an ohmic contact between the individual electrode plug pins, it is necessary in optical connectors to position a plurality of glass fibers in a precise three-dimensional arrangement so as to achieve a loss-free coupling between the terminal sections of two immediately optical fibers as far as this is possible. The objective in optical connectors is the establishment of a narrow mutual contact between the face-cut ends of the optical fibers such that the optical transition of information from one glass fiber to the other will take place with a maximum of freedom from loss. Such a mechanical coupling particularly for a plurality of pairs of optical fibers opposing each other within a plug-in connection requires, however, high mechanical demands on the mechanism for positioning each optical fiber, so that in view of the required high precision as well as the mechanical and thermal stability such plug connectors incur high manufacturing costs.
In this respect the U.S. Pat. No. 5,602,951 discloses a clamping contact plug consisting of an upper and a lower part, with the terminal sections of optical fibers to be contacted with each other being provided for insertion therebetween for a precise positional orientation of the pairs of optical fibers which are to be contacted with each other by their respective glass fiber ends. V-shaped grooves are provided in the lower part of the clamping plug, into which the individual optical fibers can be inserted in parallel side-by-side arrangement. The positioning grooves in the lower part of the clamping plug must satisfy extremely high demands in terms of their geometric arrangement and configuration for positioning the optical fiber ends, which are to be contacted with each other in a rigid manner, relative to each other most accurately by joining the respective abutting faces. This requires, however, a maximum of precision, which involves substantial manufacturing costs. Furthermore, the known plug system merely permits the coupling of eight parallel pairs of optical fibers. In view of the prevailing demands in terms of precision, however, an increase of the number of optical fiber pairs to be contacted with each other would result in a multiplication of the manufacturing costs.
The article by N. Kobayashi et. al. xe2x80x9cInjection Molded Plastic Multifiber Connector Realizing Physical Contact with Fiber Elasticityxe2x80x9d, in IEEE Journal of Selected Topics in Quantum Electronics, Vol. 5, No. 5, September/October 1999, pp. 1271-1277, discloses an optical fiber plug system in which the optical fibers to be contacted with each other run into respective plug units of an identical design, with the ends of the optical fibers ending in an unsupported section within the plug units. Moreover, an intermediate adapter element is provided which presents through-bores into which the optical fibers with their unsupported ends respectively run from opposite sides so that they abut each other in pairs within the bores. With the optical fibers running into the bores with some excessive length their length is slightly upset by the plug unit so that their optical fiber ends are pressed against each other by the additional resilience along the upset glass fibers. The disadvantage of this plug solution is the high risk of fracture of each optical fiber with its unsupported ends during the operation of joining it with the intermediate adapter unit. Apart therefrom, such a plug solution cannot be optionally scaled for a major number of optical fibers to be contacted.
The present invention is therefore based on the problem of configuring a plug for optical fibers in such a way that the optical fibers to be contacted with each other can be reliably and precisely optically coupled relative to each other while the plug should be suitable for manufacture at the lowest cost possible and is capable of satisfying maximum demands on positional adjustment of each optical fiber. Furthermore, the plug should preclude any risk of damage to the optical fibers both in the plug-in and the plug-out operations. The plug should moreover offer the possibility of connecting an optional number of optical fibers with each other at a high component density, which are disposed in a linear or array arrangement.
The object of the invention is achieved with an optical fiber connector and a method as set forth in the appended claims.
A feature of the present invention includes an optical fiber connector having a plug unit and a counter plug unit, wherein the plug unit and the counter plug unit each comprise two components, each having a receiving portion for receiving and fixing at least two optical fibers and an adjusting portion having adjusters to adjust the optical fibers in a defined position, and wherein at least the adjusting portion provides for the insertion of a connector having at least two elongate V-shaped grooves, with one of the optical fibers being aligned by the adjusting portion in each of the grooves.
Another feature of the present invention includes a method of producing an optical fiber connector having a plug unit and a counter plug unit, wherein the plug unit and the counter plug unit each comprise two components, each having a receiving portion for receiving and fixing at least two optical fibers and an adjusting portion having adjusters to adjust the optical fibers in a defined position, and wherein at least the adjusting portion provides for the insertion of a connector having at least two elongate V-shaped grooves, with one of the optical fibers being aligned by the adjusting portion in each of the grooves, comprising the steps of: inserting said optical fibers into each separate component by inserting each of said optical fibers into said grooves of said receiving portion and into said groove of said adjusting portion such that the end of each inserted optical fiber extends beyond a seating surface of said adjusting portion; fixing each of said inserted optical fibers in said groove of said receiving portion; combining said two components facing each other with their optical fibers inserted into said groove; and polishing said seating surface together with the ends of said optical fibers which partially extend into said combined components.
Various other objects, features, and attendant advantages of the present invention will become more fully appreciated as the same becomes better understood when considered in conjunction with the accompanying drawings, in which like reference characters designate the same or similar parts throughout the several views.